Conveyor systems are customarily used for transporting materials to be conveyed, such as, for example, bulk material, rock or sand from quarrying. For conveying materials over a steep section or during the conveying of hazardous materials, use is made of tubular conveyors, wherein the conveyor belt is shaped to form a tube and surrounds the materials to be conveyed.
DE 40 28 469 A1 discloses a feeding mechanism for feeding materials to be conveyed onto a conveyor belt, wherein the conveyor belt is opened from its shape as a circumferentially closed conveyor tube into a U shape for filling purposes and, after the filling, is shaped again to form a circumferentially closed conveyor tube. Said feeding mechanism is therefore suitable to be loaded at any desired displaceable position along a section. The conveyor belt here is intended to be pretensioned in such a manner that, after the U-shaped opening of the conveyor belt, the latter is automatically shaped to form a conveyor tube. The closed conveyor tube is opened into a U shape by expanding elements of the belt system engaging on the inner surface, which faces the materials to be conveyed, of the conveyor belt and spreading open the inner surface. The materials to be conveyed are input by means of a funnel from the upwardly open side of the U-shaped conveyor belt. Subsequently, the conveyor belt is closed around the entire circumference to form the conveyor tube.
A problem of material feeding of this type onto a conveyor belt which is shaped to form a conveyor tube resides in the fact that the materials to be conveyed comprise small material parts and large material parts. The large material parts have to be suitably treated here so that there is the possibility of shaping the conveyor belt to form a conveyor tube without the conveyor belt colliding with the large material parts. Large material parts may be formed here in an elongate manner, in particular if they have been processed with a rotary breaker. These what are referred to as “fish” are large material parts which are formed in an elongate manner and can reach sizes with a main longitudinal direction that are larger than the diameter of the shaped conveyor tube.
In addition, large material parts lead to considerable loadings of the conveyor belt and of the belt-guiding devices, and therefore these may even be damaged if the large material parts pass directly onto the conveyor belt. As little loading as possible of the conveyor belt is desirable, however.
Thus a need exists for a conveyor device that is designed in such a manner that high loadings of the conveyor belt and of the belt-guiding device are prevented and damage is minimized.